Jack mechanism



June 26, 1923.

's. A. s NELl.

JACK MECHANISM Filed Feb. 14

SneZZ Sam ue Z A.

' w mounted.

Patented .lune 26, 1923..

SAMUEL A. SNELL, F ST. lLOUIS, MISSOURI, ASSGNOR TO MOON VIANUFA@ TUBING COMPANY, 0F ST. LOUIS, MSSOURI, A CORPORATION 0F .ITLESSOURIL` JACK MECHANISM.

Application flied rebriiaiy 1a, 1922. seriai no. 536,521.

To all whom t may 'concern Be it known that I, SAMUEL A, SNnLL, a subject of the King of Great Britain, residing at St. Louis, Missouri, U. S. A., have 5 invented a certain new and useful improvement in Jack Mechanism, of which the following is a full, clear, and exact description, such aswill enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this application.

My invention relates to operating mechanism for ratchet jacks, such as are commonly used for motor cars, and consists in improvements upon the jack mechanism illustrated in my copending application, Serial Number 524,614.

The objects of my invention are to provide pawl moving means which shall be less expensive to manufacture, easier to assemble, and more deinitein their operation than the corresponding means shown inthe above-mentioned application and in L other jacks of this type which are now on the market. y .j Iny the accompanying drawings which illustrate a selectedlembodiment of my in` fvention, Y Figure l is a side elevation of a jack and operating handle. j

` Figure 2 is a vertical section on an en-` larged scale of the jack operating mechanism. j

Figure 3 is a similar section but showing the parts in a dierent operating position.

Figure 4 is a partial elevation of the edge of the jack looking toward the edge upon which the operating handle is Figure 5 is a detail section taken on line 5-5 of Figure 2 but with the parts kin a different position.

The jack frameil is mounted upon ya base 2 and is provided with a mechanism housing 3 in which is pivoted at 4 an operating handle 5 and a holding pawl 6. At the inner endwof the operating handle 5 is pivoted a lifting pawl 7. Pawls 6` and 7k are provided with downwardly projecting lugs 8 and 9, respectively, which extend into an opening in the lower portion of housing 3. Slidably `mountedin an extension 3a of the'housing is a plunger 10 provided with a compressed spring l1 tending to thrust the plunger upwardly into a position in which it engages the lugs 8 and 9 of the pawls. Plunger lO'is pro# vided with an eccentric linger 12 adapted to bear against the lower end `of `housing ex! tension 3a to hold plunger 10' in a retracted position in which it does not engage either of the pawl lugs. This position is indicated in Figure 5. i y

Mounted on the pivot 13 of the llifting pawl 7 is a link 14 anduniting the swinging end of this link and the, rack engaging Link 14 is provided with a laterally'expawl 7 in such a manner as to` constantly lportion of pawl 6 is a tension spring 15.` f

push the pawl into engagement with the.

rack 17. 1t will be noted that a line drawn from pivot 13 to the engagementoiffmein` bery 15 with the link and thence lto the -engagement of member 15 with `pawl`6 will j extend away from the rack and then toward f therack. In othery words, link 14 and spring l5 form a jointed tension device foi-:yields ingly moving rack. j v j `When the jack is to be used for lifting a pawls` 6` and 7` toward the load, eccentric V12 is positioned as yshown in Figure 5, andalternate liftingand lowering of. the operating handle will cause pawls 6 and`7 to raise rack 17 in the stepby-step manner common to such jacks.y

TWhen it is desired to lower a load, eccentric l12 is turned to the'position shown in Fig.

ures 4, 2 and 3 so that plunger l() engages the pawl ylug which projects downwardly the greatest distance, and yieldingly lpushes against` the lug in a direction tending to throw the corresponding pawl out of rack engaging position; j j Assuming the parts to be in a position shown in Figure 2 and a load upon the top of the rack bar, plunger 10 has thrust pawl f 7 awayvfrom the rack teeth. `Downward movement of the outer end of handle 5 will move pawl7upwardly and as plunger l() is the thereby permitted to move upwardly,

7 will release lug 9 from plunger 10 and permit the link and spring ytoggle device the latter will engage lug 8 onl the holding` pawl', further upward movement of pawl to `function and throw pawl 7 into engag ment with a rack tooth. The weight of the load on pawl 6 will result in sufficient friction between the points of the pawl ytooth and engaged rack tooth to prevent spring ll and plunger l from thrusting the pawl out of engagement with the rack.` When the upward movement of pawl 7 after engagement with the' rack, is sufficient to j slightlylift rack 17 this friction is removed andV pawl 6 is thrust outwardly by" plunger When the rack is being lowered and is supported uponpawl 7 and the load is removed, the friction between the rack tooth* aand; -pawl toot-h will be reduced so that .pas

spring ll willthrust plunger l() upwardly (to the positip'n'shown' in Figure 3,'throwing j `2iboth'of the pawls out of engagement with the rack bar and permitting the latter to drop 'to the position shown, eliminating the necessity of the step-by-step retraction of the rack 'bar throughout its full length.l i It lwill be noted that the holding pawl 6 isinounted iipon a fined pivot7 while the lifting `pawl isnioiinted upon a movable pivot, the moving of which constantly changes the relative positions of the pawl pivotsfchanges the relative projection 4of the pawl lugs 8 andy 9,1andnchanges `the ,degree although not the direction of the application ofthe joint 'edftension device forces. l refer to'pawl 17 as the lifting pawl to ydistinguish itfrom the Vholding pawl 6, although when the 'j ack iisfbeing lowered, it is not, accurately s v eaking, aliftingpawl, buta lowering paw *Pawls 6 `and 7 are preferably formed of steel stampings so as to have a'. hollow `U- shape and when asst-iinbled7 the bottoms of the U-shaped sections are facing away from each other so! that the sides or legs of the U- sections extend toward each other and provide betweenthem a receiving spacerfor link 1K4 and spring Lugs 8 and 9 are formed by the downwardlyj` projection of the transverse'bottoms of the U-sections.

The above described. construction ,elimi-` natesitlat; springs which are more expensive than coil springs and are subiectfto undesirable variations in elasticity and are usugally more difficult to assemble than coil springs y as shown. 1t will be noted-that in a jackof Ythis type there must beadeiinite cooperaationfbetween springs ll and l5. If one or vthe other of these springs is too strong or too weak,y the pawls will not be actuated `to and from thefrack bar at thenecessary instants. 'lie-provision of coilspring 15 and thefasteniiigof it to pawl 6 as shown enables it to be easily adjusted when necessary to best cooperate with spring 11.

lt will be noted that movement of either pawl about its pivot by engagement of its lug by plunger l0 will stretchspi'ing 15 and j increase the tension of the latter, thereby in creasing the tendencyof the springlto move the unengaged pawl toward the rack.

lt will be understood that the details of construction illustrated are not essential to the embodiment of niy invention as set forth in the following claims.

lhat l claim is:

l. ln a ratchet jack, a frame, a pairkoi pawls7 a coiled spring :connected at one end to one 'of said pawl's, and a link connected at Y its ends to the other end of said s ring and P e, L i

`to i'iXed point on the frame respectively and having transverse engagement with Ythe other of said pawls;

2. ln a ratchet jack, a frame,y a lifting;

rack,y a pair of pawls mounted inthe frame at the saine side of said rack, a link pivoted at one end, aycoiled spring having one end secured to the unpivoted end of saidlink and its other end secured to yone of said pawls and tendingy to pull said Vpawl toward Asaid rack and to pull said linkinto a position in which itengagesthe otherof said pawls.

3. 1n a ratchet jack, a frame7 anoperating lever fulciumedbetween its ends o'nsaid Y. frame, a lifting pawl pivoted on one endA of said handle, a holding 'pawlpivoted on said frame, a pawl actuating devicecoinprising V'afrigid linkpivoted at one endfon the pivot of one of said' p-awls and engaging the latter at apoint spaced from the pawl pivot, and a. coiled spring under tension` se- :cured at its respective ends" tothe unpivoted end of said link and to the other ofvsyaid pawls atv a point on the `latter spaced from its pivot.

ze. In a ratchet jackia lifting pawl, a holdi ing pawl7 each pivotedlnear one end, each provided witha projecting lug near its pivoted end and each having a rack engaging j tooth at its unpivotedeiid, an `operating lever for shifting said pawls bodily relative to each other, a pressure inemberengaging one or both of said lugs according to the relative positions of said' pawls, a single coil j spring secured toone of said pawls, and a link'secu'red to said spring 'and to l,a'pivo-t so as to place said spring uiidei` tension7 link contacting with the backof the lother of said'pawls,r said spring; and linkbeing arranged to pull leither Voi said pawls into rack engagingjposition when the lug of ,the

other pawl is engaged lby said member.

5. In a ratchet a lifting pawl, a holding pawlheach pivot-ed nearl one end and having a rack engaging portion spaced therefrom, a tension coiled spring connected l,to the `rack engaging portions'fof one of said pawls, anda rigid l.element connectedto said spring and actuatedthereby to exert pressure on the other of said pavvls at right angles to the axis of said spring.

6. In a ratchet j ack, a rack bar, apivoted holding pawl, a pivoted lifting paWl, a member for shifting the relative positions of the-pivots of said pavvls, yielding paWl moving means, including a coiled tension spring and a pivoted link arranged end to end and connected and acting to pull one of said paWls forwardly into rack engaging position and thrusting the other of said paWls into similar position, said means" being adapted to so move said pavvls independently of their relative position.

7. In a ratchet jack, a lifting pavvl, a holding pawl, each pivoted near one end, pro-v vided With projecting lugs, and having a rack engaging portion spaced therefrom, an operating lever for shifting said pavvls bodily relatively to each other, a pressure member engaging onel or both of said lugs according to the relative positions of said paWls, and a tensio-n coiled spring and c0- operating link connected to said holding paWl and contacting With a face of said lifting paWl adapted to move said holding pavvl being channel-shaped in cross section, and l a paWl operating element positioned in the channel of the pavvl.

In testimony whereof I hereunto aiix my signature this 8th day of February, 1922. SAMUEL A. SN ELL. 

